


Promise Me

by TintedMirrors



Category: Shadowhunters (TV), The Mortal Instruments Series - Cassandra Clare
Genre: Alec grows old, Angst, I'm Sorry, I'm just warning you, Immortal Magnus, M/M, THIS STORY IS SAD, There Will Be A Happy Ending Though, immortality issues, inspired by 3x05, mortal Alec
Language: English
Status: Completed
Published: 2018-04-18
Updated: 2018-04-25
Packaged: 2019-04-24 14:23:26
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 3
Words: 9,186
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14357304
Author URL: https://archiveofourown.org/users/TintedMirrors/pseuds/TintedMirrors
Summary: Alec is growing old. There is no way to fight it. He always thought about death and how Magnus would react when it came time for him to die, but he never considered what it was like to grow old while Magnus stayed young. He never thought about it until he starts living it.He’s in his thirties when he gets his first gray hair.





	1. Chapter 1

**Author's Note:**

> I'm sorry. I had to. I was thinking about doing this story since last week, then I watched episode 3x05 and I just HAD to. It will be a happy ending though! I swear!

Alec is growing old. There is no way to fight it. He always thought about death and how Magnus would react when it came time for him to die, but he never considered what it was like to grow old while Magnus stayed young. He never thought about it until he starts living it.

He’s in his thirties when he gets his first gray hair. It’s small and light against his otherwise dark locks, but Alec sees it purely by accident. He’s brushing his teeth, and when he glances in the mirror after washing his mouth out, he notices it pressed against his wet forehead from his recent shower. He leans in closer, takes a good look at it, and exhales loudly. It’s there and there’s no denying, but he grabs it between his fingers and tugs it out. If it wasn’t there at that moment, he couldn’t see the harsh truth taunting him in the mirror.

A few days later, Alec is lying in the bed, with Magnus’s warm body pressed against his own. He has his eyes closed, his breathing even, because he’s only just pushing his way through the morning fog of sleep. He hears Magnus murmuring something, so he keeps his eyes closed because he’s curious, and he just listens as his husband. Then he feels it, the familiar feeling of magic dancing over his body. This time, it’s over his hair.

“If you don’t see it, it was never there,” Magnus mumbles and Alec can only assume what Magnus saw. A gray hair.

Alec pretends to wake, and they use that morning to make love. When he goes to the bathroom afterwards, he realizes his hair is darker than usual, and it’s not hard for him to guess that Magnus dyed it.

Magnus does this another three times before Alec decides that enough is enough. When his husband goes to do it a fifth time, Alec grabs his wrist.

The warlock looks shocked for a moment, eyes widening. “Alexander.”

Alec blinks at his husband and smiles softly. “It’s okay, Magnus. I’m getting older and that’s okay. You can’t keep dying my hair to hide the gray.”

Magnus’s mouth pops open in surprise and he glances away, clearly embarrassed at being caught. “Alexander, I’m not ashamed of you."

Alec smiles because he knows. He knows Magnus was only doing it for Alec’s own feelings. He never wants Alec to be afraid of the future, of Magnus one day losing him.

“I know.” He kisses Magnus gently. “I love you.”

Magnus grins and caresses his cheek. “I love you too.”

•••

Alec is in his forties when he notices that he’s slowing down. By this age, a lot of Shadowhunters have retired from the field, preferring to take seats on the council or other administration tasks. But Alec hasn’t, and he realizes at this point that it was a bad idea. The demon comes at him quick and hard and he barely escapes with a roll away from the sharp claws.  
He hears Jace shout his name, but it’s too late and he feels the claw of another demon slice his shoulder. He shouts as severe pain shoots through his body and his knees give out from underneath him.

The demon goes to attack again, but Jace is there with his seraph blade, slicing the monster open. The screeches is all they hear as it shoots into the air and away from the Shadowhunters.

Jace crouches beside him. “Are you okay, buddy?”

His shoulder is throbbing in pain and his heartbeat is loud in his ears, but he’s okay. He can handle pain, just not as well as he did when he was younger. He nods, short and stiff, but Jace snorts at him.

Jace draws an Iratze rune on his forearm to slowly heal his gash and with one phone call to Magnus, a portal opens and Alec portals home.

Magnus is waiting for him, an anxious expression on his face.

“Alexander, you’re hurt.” He reaches for Alec immediately, his magic humming as it dances from his hands and over Alec’s shoulder. With the mixture of the Iratze rune and Magnus’s magic, he heals quickly, the gashed skin gnashing together until his shoulder looks like it had before he was injured.

“Where’s the kids?” Alec asks as he rolls his arm, testing out his shoulder. His joints crack, but it feels normal. He says kids, but they aren't kids anymore. Max and Rafael are practically adults.

“They’re in bed, where we should be.” Magnus frowns at him. “I told you to be careful.”

He did, and Alec had listened, for the most part. It wasn’t like he meant to get hurt.

“Alec…” Magnus exhales and grabs a tumbler sitting on the bar. He passes it to his husband and Alec drinks it in one gulp. It burns its way down his throat, but Angel, it tasted good. “Maybe it’s time for you to retire from the field.”

Hearing it from Magnus lips hurts, because even though it’s true and it is time, it’s worse coming from his husband. It’s another reminder that while Magnus can go on with his business of being the high warlock, saving lives, Alec must give up the physical part of his job because he’s _getting old_.

He doesn’t like fighting with Magnus, so he just smiles. “Maybe.”

Magnus has known him for too long though. He touches Alec’s arm gently. “Alexander, I’m not saying this to hurt you.”

“I know.” Alec rests the tumbler on the bar and grabs the bottle of alcohol, filling the glass halfway. He drinks that in two swallows.

He feels Magnus’s eyes on his back and the tension in the room is thick. He hates coming home to this. He hates not communicating with his husband, so he closes his eyes for a moment and looks at Magnus.

“I’ll retire from the field tomorrow. I’m the head of the institute anyway, I shouldn’t be doing field work.”

Magnus’s brows furrow. “You’re not okay,” he says softly.

No, he’s not, but he just smiles. “I’m fine, Magnus.” He takes two steps, then kisses Magnus gently on the lips. “I love you.”

Magnus is hesitant, but he returns the smile. “I love you too.”

•••

He’s in his fifties when someone actually makes a comment about his relationship with Magnus. It’s at Rafael’s wedding to a beautiful young Shadowhunter who stole his heart from the beginning. She is a beautiful blond woman that reminds Alec a bit of Lydia.  
They are at the reception, when Magnus kisses him gently on the lips. “I’m going to have a dance with my new daughter-in-law,” he says.

Alec nods and watches Magnus saunter off toward Rafael and Adele. Rafe laughs at something Magnus says and takes a step back, letting his Pa dance with his new wife.

Alec can’t look away from his husband, who looks radiant in a soft silver suit. He is the most beautiful person at the wedding and Alec thinks about how lucky he is to be the one who married such a man.

A familiar man drops in the chair next to his and he smiles politely. Adele’s father is a gruff Shadowhunter who is only a few years older than Alec is. He's the kind of man that Alec has butted heads with before, the kind who hated Downworlders for racist reasons. But Alec stays polite because he knows that's what Rafe wants and he hates upsetting his son.

Adele’s father, Steven, clears his throat. “Our kids are married now.”

Alec tilts his head in acknowledgement. “They are.”

“Never thought I’d see the day when my little girl got married.”

Alec understands that sentiment well. He remembers when Rafe was just a little boy, sitting on his daddy’s lap while Alec did paperwork at his desk. Now, Rafe is in his thirties and married. It is hard to believe.

Magnus and Adele laugh as they spin around the dance floor as though they are professional dancers rather than amateurs. Alec supposed in some way Magnus is a professional. He’s been dancing for over four hundred years after all and Magnus has told him about some of the wedding he’s attended.

“How does it feel?”

Alec frowns at Steven. “How does what feel?”

“Not being able to keep up with your husband?” He smirks and Alec wants nothing more than to punch it off his face. “I mean, he stays young and you get old. Must be hard with all the young men and women sniffing around your husband.”

Alec bites the inside of his cheek to stop himself from saying something he’ll regret, and he takes a moment to think of something diplomatic. He is the head of the New York Institute. “Magnus and my relationship isn’t based on our looks.”

“Says the one who’s growing old.” Steven laughs as he stands again and saunters away.

His words hit Alec hard because it’s true. He is the one growing old and Magnus is chained to him like a pet. He knows Magnus and he knows Magnus would never leave him, but now he begins to wonder if it’s because he feels like he has no choice but to stay with Alec.

Those thoughts are toxic and Alec can’t bring himself to ask Magnus about it.

•••

In his sixties, Alec feels his age. As a Shadowhunter, he looks younger than he would if he was a Mundane, but he hates what he sees in the mirror, especially when he’s standing beside Magnus.  
One evening, Alec is brushing his teeth after just exiting the shower, when a shirtless Magnus enters the bathroom. He kisses Alec gently on the shoulder and attends to his hair.

Alec stares at him in the mirror. No, he stares at _them_. They are so different, with Alec’s gray-infused light black hair and aging face, and Magnus’s dark black locks and gorgeous young skin. It’s moments like this that hit him hard.

Magnus smiles at him. “Are you nearly ready? Reservations are for seven.”

Alec smiles and nods, trying hard not to let it worry him. Magnus loves him.

When they arrive at the Mundane restaurant, a young hostess greets them and Magnus happily greets her in return. Straight off the bat, the flirting begins. She’s not coy about it and Magnus takes it in his stride with a quick laugh. He reaches for Alec’s hand, but Alec moves it away before his husband can touch him. It makes Magnus frown at him.

When she has them seated, the questions begin.

“What was that about?” Magnus asks.

Alec shrugs as he stares at the menu. He can’t look at his husband, not when he feels this way. Going out is just another reminder of how differing their looks were. Magnus is young, he is old. Magnus is flirted with by women and men and Alec is invisible, an elderly man who means nothing to them. He doesn't blame them.

“Alexander…” Magnus’s hurt tone breaks Alec’s wall.

“I just don’t think it’s appropriate for us to hold hands in public.” Alec glances around the room, but no one is paying attention to them.

“Why?” Magnus is gorgeous in his confusion, but he knows why. Of course he knows why, and Alec hates it when Magnus acts innocent about it.

“Look at me, Magnus,” Alec hisses, leaning closer. “I’m sixty-five.”

“And I’m four centuries old.”

Alec holds up a hand. “Don’t, Magnus. Don’t do that. You know how this looks.”

Magnus’s eyes flash with hurt. “Alexander, don’t. Please. I just want to spend a night with my husband.” He reaches for Alec’s hand and grasps it in his own. He raises it, presses a small kiss on his palm, and smiles. “I love you.”

Alec can’t bring himself to feel uncomfortable about the action when Magnus was so genuine about it. He grins in return. “I love you too.”

A waiter clears his throat and Alec startles, not even realizing he was there. Magnus is like a drug to him and even his surroundings disappear when his husband steals his attention.

“What can I get you?”

Magnus orders his meal without even looking at the menu. They’ve been here a couple of times before and Magnus sticks with what he likes.

“And for your grandfather?” The waiter says, a flirty smile on his face that he aims at Magnus.

Alec snaps his hand out of Magnus’s, eyes wide, heart thumping painfully in his chest. The words are like ice sliding down his back, a jolting reminder of where they are.

Magnus mouth parts angrily and he glares at the waiter. “He’s my husband.”

The waiter stutters out an apology and takes the menus, stumbling off like a hurt puppy dog.

“What a tool,” Magnus grumbles. He holds out his hand again, waiting for Alec’s, but Alec shakes his head.

“Not here,” he says, as he holds his hands in his lap.

That dinner is an uncomfortable mess, with Magnus sulking over Alec’s reaction. When they get home, Magnus goes to kiss Alec, to start something that will end with them in the bed, but Alec doesn’t want to, not tonight. So, he briefly kisses his husband and tells him he’s staying up for a little while longer.

With a sad glance, Magnus goes to bed.

Alec watches him go and it’s only when he sees Magnus close the door to their bedroom that Alec feels like he can breathe again. He can’t keep doing this. He can’t keep hurting Magnus’s feelings. Magnus may not care about what others think, but Alec does. He’s tired of being looked at like a cradle snatcher. It hurts to think about, but he knows what he must do. For himself. For Magnus.

The next morning, Magnus kisses him on the lips and heads out for an appointment. Alec takes that chance to pack up some clothes and belongings. His belongings are entwined with the loft, they are a part of it because he’s lived here for so long, so he can only take the important things. The things he knows he’ll need.

He makes it to the family room when the door opens.

Alec holds his breath, expecting to see Magnus.

Instead, it’s Catarina.

She pauses at the sight of him, her eyes dipping to the bag in his hand. She doesn’t look surprised. She sighs. “Where are you going?”

“I don’t know.” Alec feels his chest constrict, his heart beating a little bit faster. It hurts to think about what he’s doing, but he knows it needs to be done. For all of them.

“Can you at least tell me when you get there? So I keep an eye on you?” There’s anger in her gaze, but also understanding.

“I can’t.”

She nods, and swallows deeply. “You’ll break his heart, Alec. No. You’ll shatter his entire being. He loves you.”

“I know.” The tears flood his eyes and he blinks. One lone tear trails down his cheek. “I love him too, but I can’t ask this of him anymore.”

“Ask this of him?” Cat shakes her head. “He never wanted anything else.”

“Look at me, Cat.” He gestures to himself. “I’m old.”

“Not to him, you’re not. You’re his Alexander. His husband.”

Alec’s eyes slip closed.

“You don’t have to do this,” She whispers. Her tone is desperate now, begging him not to go.

“I do have to. For us.” His fists clench, pain enveloping his heart. Why did it have to hurt so much? He can’t breathe.

“Not for us. For you,” she snaps. “You are the only one who cares about what other people think.”

Alec opens his eyes and sees the pain so obvious on her face. It reminds him that he’s not just leaving Magnus, he’s leaving his friends too. He’s leaving Cat. They’ve become close over the decades and by walking away, he was leaving her behind too. And his children. And Madzie. But it was for the best. It had to be.

“I’m sorry.” He squeezes her shoulder and kisses her on the cheek. “It’s for the best.”

“Alec, _please_ don’t do this. If you leave, I can’t fix him. You’ve meant more to him than anyone he’s been with before. You have a family with him. What about your boys? What about them?” Her voice is raw, tears cascading down her dark cheeks.

“I’ll write to them.” His sons are grown men now. He’s done his job in raising them and he couldn’t be prouder. But they don’t need their elderly dad anymore. “And Magnus will move on.”

“You idiot,” Cat hisses. “If you think Magnus could move on from you—”

“Goodbye, Cat.” He walks around her and heads toward the door. He pauses at the threshold. “Promise me something?”

“What?” She asks without turning to look at him. Her shoulders are shaking, her small sobs audible.

“Promise me you’ll help him move on from me. Make sure he doesn't try and find me. It's better if I die alone.”

He didn’t wait for an answer before he walked out the door.


	2. Chapter Two

The day Magnus comes home to find Alec gone, he is angry. 

Catarina waits for him and the moment he opens the door, she stands from her chair. Magnus peers at her with a smile.

“What are you doing here, dearest friend?” He asks as he throws the heavy book he’s carrying on the sofa. The meeting he attended to has tired him. It was a summoning and while he’s usually against such a thing, the warlock pays him handsomely.

He watches as his old friend exhale. “I came to tell you about Madzie’s new boyfriend.”

Magnus chuckles. Catarina and he love gossiping about her adopted daughter’s love life. They are parents and it’s what they do well.

“Did Alec let you in?” He asks as he makes his way over to the bar. He makes himself a martini and takes a sip, moaning at the delicious burn. 

“Magnus…”

It’s here that he notices the strained tone in her voice and he spins on his heel, eyebrows furrowed. “Is this new boyfriend trouble?” he asks, his jaw tightening. Madzie is like a daughter to him and Alec, and they’d never let anyone hurt her.

“Magnus…” Catarina’s bottom lip shakes, a rare reaction from her.

“What did he do?” Magnus growls. “Wait. Where’s Alec? He’ll want to hear this too.”

Magnus drops his glass of martini on the bar again and strides toward the bedroom. It’s late afternoon and his husband is probably having a nap.

“Alexander, where are you? Catarina has something to tell us.” He shoves open the door, but the room is empty. Too empty. Alec isn’t the only thing that’s absent in it.

The closet’s doors are open and shelves that once housed Alec’s favorite clothes are empty. The section where he keeps his weapons are empty as well, bare of any traces that something was there to begin with. It makes Magnus pause.

His hand grips the door threshold and his chest constricts. Logically, he knows what this means. He feared this day, but he never thought it would happen. He never thought his husband would leave him. They figured out their problems about Alec’s aging, he was sure they had.

Magnus doesn’t want to believe it, so when Catarina’s hand settles on his shoulder, he shrugs it off and heads toward Alec’s side of the bed in a mad rush to open the drawers of his bedside cabinet. They are just as empty. There’s no seraph blade that Alec keeps in there for protect them, or book that he reads before he goes to sleep. There’s no photo of them and the boys that usually sits on the top of the cabinet either, just the lamp that taunts him.

“Magnus…” Catarina’s voice is low, and he can hear the tears. He doesn’t need to see them.

“Did you help him leave?” Magnus asks. The reality is sinking in now that he sees the emptiness of the top drawer, and his fear and pain overwhelm his senses. He can still smell Alec’s aftershave, a spicy and masculine scent that dances through the room from their joined bathroom, and the bed still has an indent in it from where his husband slept the night before. The bed isn’t made, because Alec never makes it after he gets up in the morning.

“Of course not.” She sounds insulted that he even asks her.

“Then how did you know?” He pivots toward her, jaw tight. His fists are clenched at his side, but he can feel his magic pulsing through his body, looking for an escape. His emotions are erratic, which makes his magic unstable. Magnus can feel the power in his fingers, begging for release, but he can’t. He knows he must stay focused.

“I saw him when I came in.” Catarina knows better than to reach for him. She keeps her distance.

Magnus blinks away the tears that start to build. He doesn’t have time for that. “Why didn’t you stop him?” He yells unexpectedly. It makes him lose control briefly and his magic sizzles in his fingers, a burst of it attacking the floor and singing the carpet, before Magnus gets it under control.

If Catarina is afraid, she doesn’t show it. Her posture is taut and controlled. “He’s a grown man, Magnus. I couldn’t have stopped him.”

“You could have,” he snaps. The tears have broken and are lining his cheeks with trails, but he doesn’t bother to wipe them away. His husband left him. His husband of decades packed his belongings and walked out their door. He’s allowed to cry. “You could have paralyzed him until I got here. I would have made him listen to reason.”

“He would never have forgiven me,” Catarina says softly.

“He would have eventually.” Magnus shakes his head and takes a step back from her. He’s never felt betrayed from Catarina until now, until she let his husband walk away from him. “Leave.”

Catarina takes a step forward now. “Magnus, you can’t look for him.”

“ _Leave_.” The power and warning in his voice leaves no argument, but it’s Catarina and she’s known him for too long. She’s not afraid of him.

“Alec could come back to you. Maybe he needs time to think.” 

She sounds so hopeful, it makes Magnus ill to the stomach. It’s churning, a reminder of all that he’s lost over the years. He’s dealt with grief before, but not like this. Alexander is different, he’s always been different. He’s touched Magnus in ways that no one else has.

His hands shake against his thighs as the tears continue. He needs to control himself, but he doesn’t have the strength. Not right now.

“I need to find him.”

“He doesn’t want to be found, Magnus.” She takes another step forward, but doesn’t reach for him.

“He doesn’t get that choice,” Magnus snarls. He sounds almost animalistic, with his voice low and raw. “He didn’t leave me because he doesn’t love me, he left me because he’s afraid of the way they look at us. He’s afraid because he doesn’t want me to see him die.”

“Is that such a bad thing? How many people have you loved that you’ve seen die, Magnus?” Catarina shakes her head. “Alec loves you and he only wants to save you the heartache.”

Magnus laughs cruelly. “Save me the heartache? How does that work, Cat? Am I not heartbroken now?”

“It’s different, you know that. He doesn’t want you to see him die.”

He snorts. “Is that his words?”

Her silence is all the answer he needs.

“Catarina, I love you, but either help me or get out of my way.” He steps toward the door that she’s blocking, and when he nears her, he pauses, waiting.

Catarina sighs and steps aside. “He doesn’t want you to find him, Magnus.”

“I don’t care what he wants.”

That day, he calls everyone he knows. He uses whatever tracking he can get his hands on, but they don’t find his Alexander. No matter what they try, what they do, there’s no sign of him.

Magnus goes a week without sleep, before Max decides enough is enough and tricks him into drinking a sleep potion.

•••

It’s been two months since Alec disappeared and Magnus is no closer to finding him. He’s a mess, both physically and emotionally. His magic is warring with his body and he’s beyond exhausted, but day after day, he keeps searching for ways to bring his husband home.

Max and Rafael receive letters from Alec once a week, but even those letters hold no clue as to where to find him, and no way to contact him in return. The letters mainly reassure them that he’s okay and explains some of the things he’s working on, but they don’t clue Magnus in on where he may be staying. Alec talks about Magnus in the letter, as though he knows Magnus will be reading it. He apologizes for leaving, and explains his reasoning and asks Magnus not to look for him, but it only makes Magnus angrier. 

_He will not let Alec go. He will find him if it’s the last thing he ever does._

Magnus is talking to a warlock he knows on the phone. Humphry is one of the best trackers in the world, but he costs a pretty penny. Magnus doesn’t care. But like everyone else, Humphry hasn’t found a trace of Alexander.

“How is that possible?” Magnus growls into the phone.

“It’s clear that he has a very strong warlock protecting his location. There is no other explanation, Bane.”

“How do we identify who’s magic it is?” Any other day, he’d know, but Humphry is the expert when it comes to tracking.

“We don’t. I can’t tell what sort of magic it is, let alone who it belongs to.”

“If I knew you were this useless, Humphry, I wouldn’t have spent money on your services,” Magnus snaps as he slams the end call button.

The door to his—their—loft opens, and Catarina walks through.

“Didn’t I tell you that I don’t want to see you again until I find Alexander?” He sends her a narrowed glance.

“I know what you told me, but I chose not to listen.” She stalks toward him. “I’m here to help you look for him.”

“I don’t need your help.”

Catarina sighs loudly. “Stop acting like a child, Magnus.”

“You let my husband walk out of my life, Cat. How can I forgive that?” He rises from his study table and crosses his arms.

“He’s a grown man, Magnus. It was his choice.”

Magnus laughs and shakes his head. “You still don’t get it, do you?”

“Of course I do!” It’s the first time Catarina raises her voice to him. They’ve had arguments in the past, but not like this. She’s beyond angry, he can see it in the way she loses control her magic and her skin flickers between it’s natural blue and the dark skin she’s adopted for Mundanes. “You forget that I love him too, Magnus.”

Magnus pauses because it’s true. Alexander has had a strong impact on a lot of people’s lives, including Catarina's. Over the decades, they’d become the closest of friends, with Cat approaching Alec with a problem first rather than Magnus. And his heart aches at the revelation of how hard he’s been on her. His anger at her has made him forget a lot of things, like how much she means to him too.

“I’m sorry.” He falls back in his study chair, his hands shaking as they cup his face. Fresh tears pool in his eyes. “I can’t live without him, Cat.”

Cat is at his side in seconds, her arms wrapped around his shoulders as she brings him against her body. “I know, Magnus. We’ll find him. I promise. I’ll help you.”

His shoulders wobble under the force of the sobs that wrack at his chest. “Alexander is different. He’s always been different.”

“I know.” She presses her forehead against his temple and holds him tighter. “Have you talked to Izzy and Jace?”

He accepts the hug freely because it's comforting. “They said they haven’t heard from him.” But it’s a lie, he can tell in the way Izzy avoids his eyes or the way Jace makes excuses to leave. He pushes the issue, but neither give up the information he wants, and he knows better. They are loyal to Alec, and even if they don’t agree with Alec's actions, they wouldn’t give him up to Magnus.

“We’ll find him. I promise.”

•••

Five months after Alec leaves, they still haven’t found him.

Magnus is emotionally numb by now. He feels lost and alone and every day, he stares at his favourite picture of him and Alec. It was the time they went to Paris for their fifth wedding anniversary and stood on top of the Eiffel Tower, looking so completely in love. It’d been a perfect night, one of many in their decades together.

At night, he lays in their bed and caresses the empty spot at his side. The spot where Alec’s warm body would usually fill. He fists the sheets there and curses his husband’s name, begging him to come home, before he falls into a restless slumber that consists of dreams of Alec’s beautiful face. 

In the mornings, Magnus sits at the breakfast table by himself, eating French Toast that doesn’t taste as good as Alec does it. He stares at Alec’s empty chair and clenches his eyes closed, imagining the day when his husband will walk through the door and apologize for leaving. It never comes. 

During the days when he’s actually productive, he continues to search for Alec. He can’t bring himself to stop because he needs his husband in their bed again, in their home, and in his arms. He needs to make Alec understand that he doesn’t care what he looks like, or how old he is, because Magnus will always love him completely.

One day, Magnus is at his desk, researching immortality myths. They were the kind of myths he should have been researching years ago, when they first married, and Alec began to voice his worries.

Rafe bursts through the door. “Pa!”

Magnus’s gaze shoots up to his son. “What happened?”

“Dad hasn’t written this week.” Rafe’s olive skin is flushed, his eyes wide. “He always writes, but he hasn’t written to me or Max. I rang Aunt Izzy, but she can’t get into contact with him.”

Fear grips at his heart and for a brief moment, he’s frozen. His limbs heavy as horrible thoughts fill his head. He imagines Alec sick and alone, needing medical help that Magnus can’t give him because he didn’t know where he was. It makes him nauseated. 

“Pa?” Rafe’s worried gaze drills into him.

“Does Izzy know where he is?”

Rafe swallows, and nods. “They already searched there, it was empty. He’s gone.”

Raw anger hits him. “She knew where he was and didn’t tell me?”

In his heart, he knew it was true. But it hurts to hear it

His son’s face twists in uncomfortableness. “She said Dad made her promise not to tell us.”

“I don’t care!” The window behind him shudders as his untameable magic bursts from his fingers. A pot plant smashes into pieces and a photo of their family that hangs on the wall shatters on the ground beneath it.

“Pa! Please.” Rafe swallows, sad eyes begging. “Please.”

It’s a reminder that Rafe and Max have suffered too. They lost their dad. The thought is enough for him to grab control of his magic again.

“I got this letter today.” Rafe shoves his hand in his pocket and pulls out a small piece of scrunched up paper. He passes it to Magnus.

Magnus doesn’t waste time. He opens it and reads.

_My Dearest Magnus,_

_I do believe you are looking for something very precious to you. I may know where to find him. I may even have him. You cannot say that I do nothing for you, my son. It’s very rude of him to walk out of your life, but I will fix this problem you have. For that, I promise._

_So come to me, Magnus, for I have a gift for you. You know where to find me._

_I sent this to your son because your wards are too strong for me to enter. I am proud of your power._

_Your father._.

Magnus’s breath catches as he stares down at his father’s elegant scrawl.

“Pa?” Rafe’s worried tone filters through the fog in Magnus’s brain.

“Asdmodeus has your dad.”

“Asmodeus? Your father?” Rafe’s cheeks pale. “Will he hurt him?”

Magnus’s eyes flicker and he can feel the breakdown of his façade. He stares down at the letter through his cat eyes. “He will regret it if he does.”

“What will you do?”

“I’m going to bring your dad home.”

**Notes for the Chapter:**

> Comments and kudos are amazing. Just so you know ;)


	3. Chapter 3

**Notes for the Chapter:**

> It's finally here! And I'm sorry it took longer than expected. My brain has not been cooperating and I've hated everything I written...I hope this at least meets your expectations. It hasn't been edited, but I'll probably reread it again tomorrow and fix any mistakes. I just needed to get it to you asap. *hits brain*

It’s been three months since Alec left Magnus and he’s emotionally exhausted. He knew it was going to be hard, but he never expected it to be like this. 

Nights without Magnus are hell, and as he stares at his empty bed, he wonders why he was so stupid. He knows that he can pack up and go home, but he won’t. Not because he doesn’t want to, but because he doesn’t deserve to. He reminds himself that he wants to protect Magnus, and he can only do that by staying away. It’d hurt his husband a lot more to see him die, rather than to just _know_ he’s gone. This was for Magnus as much as it was for himself too. He won’t be a burden to his husband.

One night he finds himself at a bar, wallowing in a glass of expensive bourbon. It burns its way down his throat and it’s just how he likes it. The night is young, as is many of the patrons. Alec feels ancient in the same room as these men and women, but he’s found himself bored over these last few months and people-watching has become a pastime of his. Most times, he’ll find himself comparing men and women to people he knows. He’ll always find a way to compare men to Magnus, like how they walk, how they talk, and even the type of clothes they wear.

This evening, he glances at the door as it creaks open, and an Asian man strides through. Alec watches him carefully because while it’s most definitely not Magnus, he looks very similar to him. His dark hair, golden skin, and sharp jawline is almost identical to his husband’s, and Alec can’t help but be enraptured by the new presence in the room. He has no romantic interest in the man, but if he squints, he can pretend it’s Magnus who’s sending him a smirk. Because pretending is the only thing he can do now without the love of his life. He never approaches these men though, because Magnus is the only one for him.

The man sashays his way to the bar, and Alec rips his gaze away from him. It’s rude to stare and he doesn’t want the man to get the wrong idea. But when the stranger sits beside him on one of the barstools, Alec stiffens.

“Hello,” the man greets.

Alec glances at him and sends him a small smile. “Hi.”

The stranger holds out his hand. “I’m Aisu.”

Alec shakes his hand, only because it’s polite, but the man’s skin feels strange. Unlike Magnus’s soft skin, the stranger’s hand is rough and course, yet looks as smooth as Magnus’s. It is a weird sensation. “I’m Alec.”

“Short for Alexander?”

“No.” Alec says it sharply and he bites his bottom lip when he realizes how rudely it comes out. Alexander is for Magnus only.

Aisu smiles and there’s something almost sinister about it. Alec’s instincts are going haywire, a warning that he can’t ignore sounds in his head.

“Can I buy you a drink, Alec?”

“No, thank you.” Alec slips from his stool and grabs his jacket. He’s many things—stupid for leaving Magnus being at the top—but he’s not foolish enough to ignore those instincts. He’d been trained not to. “I have to head out.”

“Stay,” Aisu purrs. “Let me buy you a drink.”

Alec takes a moment to assess the man in front of him. He has the same jawline as Magnus, and his chin is similar, but those eyes are nothing like his husband’s. Magnus’s eyes are soft, welcoming, while Aisu’s hold an ominous promise. The fact that he reminds Alec so much of Magnus would have been a coincidence, if Alec believed in them, which he doesn’t. Of all the bars that this Magnus lookalike enters, he chooses the bar Alec drinks in. He doesn’t accept this as purely by accident. He can’t.

He nods at Aisu and heads towards the exit. As he walks along the long stretch of road, his back prickles and his skin tingles. He can _feel_ someone following him.

He takes a right turn, down an alley, and pivots on his heel. His hand hovers over his thigh holster, where a seraph blade sits for protection.

As Alec suspects, Aisu heads down the same alley Alec takes. He pauses when he sees Alec and smiles. “Hello again.”

“Who are you?” Alec hisses as he grabs his blade. He whispers an angel’s name and the blade lights up.

Aisu’s face twists, a malevolent smile curving across thin lips. “I’m your salvation.”

He attacks with enough speed and power that Alec doesn’t have a chance to retaliate, not in this older body that’s starved of Shadowhunter training. And very quickly, he meets his old friend, the darkness, but not before seeing cat-like eyes flashing at him.

•••

Magnus knows where to find his father because Asmodeus makes sure of it. His father’s ring sits heavy in a chest that Magnus keeps hidden. He has never had any use for it, but he’s always kept it in case there came a time when Asmodeus revisited the living. That time is now, and he has Magnus’s husband.

Anger fuels his magic as a tracking spell hums over the heavy ring sitting in the palm of his hand. Red wisps strike the metal until visions appear in front of Magnus’s closed eyes and he pinpoints where his father is. He returns the ring and locks the chest again.

“Let me come with you, Pa,” Rafael begs when Magnus grabs his jacket.

“Absolutely not.” Magnus doesn’t glance at his son as he heads toward the door.

He doesn’t make it far before Rafael grasps his arm, tugging him around. “Please. If he has Dad—”

“I said no.” Magnus’s voice softens, and he pats Rafe’s hand reassuringly. “Asmodeus is dangerous and I don’t know what he wants. If he has your dad, I’ll bring him home, I promise.”

“And what about you? Will you come home also?” Rafe’s big brown eyes stare pleadingly at him.

“Of course.” He sends his son a lopsided grin. “How else can I punish your dad for leaving if I’m not here to do it? He will hear me bitching about his stupid actions for the next twenty years.”

Rafe smiles. “Twenty years? You hold a longer grudge than that, Pa.”

Magnus chuckles. “I do, don’t I? It’ll probably be for fifty then.”

Rafe’s smile falls and he blinks at Magnus sadly, and Magnus knows why. Alec is sixty-five, and the chances of him living for another fifty years is unlikely, but Magnus doesn’t want to think about that. What he needs to focus on is getting his husband back, no matter what. He’d rather spend another two years with his Alexander, than none at all.

“I’ll be home soon.” Magnus pries Rafe’s hand off his arm and squeezes it between his hands. With a final reassuring smile, he leaves the loft with a determined stride.

The motel he heads to is a small, two storey building. It’s old, with rickety stairs that makes Magnus wonder if it’ll collapse under his weight. It’s not the kind of place he expects his father to be, but as he makes his way to the room number that flashed at him in his vision, he takes a deep breath, ready for whatever is waiting for him on the other side.

As he reaches the door, it opens to reveal the prince of hell.

Asmodeus is just as Magnus remembers. Tall and slim, with cat-like eyes that are similar to his own. The last time he saw his father, Asmodeus had killed another one of his children and asked, not very politely, for Magnus to join him in Edom. Magnus had refused.

“Asmodeus.” Magnus’s jaw clenches and his hands curl into fists at his side. He can feel his magic warring inside as the pressure of uncertainty and anger surges in his gut. His father is blocking the doorway, which means Magnus can’t see inside, and that increases the waging emotions that threaten to take control of him. He wants—needs—to see Alexander.

“Am I not your father?” Asmodeus says, a smirk flickering across his thin lips.

“Where’s Alexander?” 

Magic sparks at his fingers and he notices Asmodeus’s gaze flicks to them curiously.

“Now, now, Magnus, I never knew you to be impatient.”

Magnus fights for control of his body, but he doesn’t have enough control to keep his warlock mark hidden. His glamor slips and he blinks at his father through his yellow cat eyes. “Where. Is. Alexander?”

Asmodeus’s chest rumbles in laughter, but he steps aside.

Magnus surges over the threshold and into the room. It’s small, and just as old as the outside, with threadbare carpet and battered old walls. Against the right wall was a bed, it’s frame thin and mattress frayed. But it’s not the bed that Magnus is interested in, rather the body lying on top of it.

Alec’s eyes are closed, his body splayed across the queen-sized mattress. His chest rises and falls, but Magnus doesn’t need magic to sense that he’s unconscious.

“Alexander,” Magnus whispers in relief, rushing over to his husband. He falls onto the bed and cups Alec’s cheek, caressing the skin. He’s cold—too cold—and fear grips at Magnus’s heart. His hands begin dancing over Alec’s chest and magic curls through the air, touching and feeling his husband’s life presence. It’s there, but it’s weak.

He spins around to glare at his father, the magic already pulsing in his veins again. “What did you do to him?”

Asmodeus’s lips twist and he blinks innocently at Magnus. “Nothing that he didn’t want.”

Magnus’s heart freezes in his chest. All the possible scenarios run through his head and it’s all he can do not to stand and concentrate every trace of his magic on the prince of hell in a blast of anger. He grits his teeth. The only thing that stops him from doing it is the touch of Alec’s skin beneath his fingers. His husband has always been a grounding factor in his life since he walked into it.

Magnus rises from the bed, jaw still clenched. “Wake him up.”

“I cannot do that, Magnus.” Asmodeus smiles smugly.

“Why not?” His fingers tingle and he curls them into a fist.

“Because my magic is still working.” Asmodeus twirls his hand dramatically. “It needs a couple more hours at least.”

Warning bells sound in Magnus’s head and he glances quickly at Alec. His husband still hasn’t moved and if anything, his skin appears to be growing paler. It’s clammy as well, sweat clinging to his forehead.

“I’m giving you one warning, Asmodeus. Wake my husband up.” Magnus’s eyes flash and he’s glaring through his cat eyes at his father. 

Asmodeus rolls his eyes. “Do you think you scare me, my son? I’m giving you a gift.”

“How is this a gift?” He hisses, taking a step forward.

“You’ll see.”

But Magnus doesn’t want to see. Asmodeus has Alec under some sort of spell that he doesn’t recognize, and his protective instincts are on high alert. He won’t let his father hurt Alec like he’s hurt his own blood and flesh. No. Magnus would never allow it.

He raises his hands and crimson magic surges out of them, straight toward Asmodeus. But the prince is too quick and he spins out of the direct line of it, attacking with his own wave of energy. The energy is different from warlock magic and it sends Magnus stumbling backward. It doesn’t take much to regain his footing though, and another surge makes the room shake under the force of it. They begin a dance of attacks, one after another, from magic to energy. With each attack, they either avoid or block it. They are matched in powers and it’s frustrating.

“Enough of this, Magnus,” Asmodeus snaps. He spins, a burst of energy sending a flower vase hurling toward Magnus.

Magnus ducks, his eyes glowing in anger. “Wake him up.”

Asmodeus rolls his eyes and shoves his fists in Alec’s direction. The room shakes violently and Magnus hurls himself in front of his husband before the dark magic can reach him. It sends him flying backward, his body slamming against a wall. It cracks and crumbles under the force and Magnus slides to the ground, along with big chunks of plaster. A particularly large piece lands on his knee and he cries out in pain. Something jagged in the plaster pierces his skin. It cripples him and his magic falters under the agony. 

He feels Asmodeus’s presence in front of him and Magnus dutifully raises his gaze. “Why are you doing this?”

Asmodeus smirks and Magnus is reminded how much he hates his father, and why he hates him. “For you, my boy. And for me.” He crouches, his face annoyingly close to Magnus’s own. “I want something of yours, but to take it, I must give you something you desire in return. That’s the only way it can work.”

“Go to hell,” Magnus hisses.

Asmodeus twists his hand in the air and the plaster suddenly feels heavier on his knee, the sharp part of it digging deeper into his skin. Magnus screams in agony.

“You don’t get a choice.” The demon lays a hand on Magnus’s chest and does _something_. Magnus doesn’t know what it is, but the pain it causes is ten times worse than the agony of his knee. It feels like he’s being ripped apart and he can’t breathe. His chest is heavy and his magic is limp inside of his body and he just _screams_ because it hurts that much.

But it’s over in seconds and Magnus can breathe again. Whatever he wants, he’s got now because Asmodeus stands and smirks. “Thank you, my son.”

“What…what did you do?” Magnus pants around the discomfort. 

“I took a piece of you. Isn’t that obvious? I need to create an army, Magnus, and you are my most powerful child. To create a powerful army, I need only the most powerful magic.”

“You…you…” Magnus’s world is growing darker and no matter how hard he holds on, he can’t. He’s losing consciousness. He glances at Alec, at his prone body on the bed.

“Oh yes, you’re husband.” Asmodeus’s hand shoots out in Alec’s direction and a pulse of dark energy beats through the air between them. Then suddenly Alec is screaming, his back arching off the bed.

“No!” Magnus yells, but Asmodeus isn’t listening.

Alec’s screams are raw and full of pain, but Magnus is too tired, too hurt to do anything but listen. And as darkness preys on his consciousness, he falls into sleep with the sounds of his husband’s agony for nightmares.

•••

By the time he wakes up again, it’s dark, and it takes a moment for Magnus to realize where he is. He’s lying on the ground, his cheek pressed against the beige threadbare carpet of the old motel.

His heart seizes in his chest and he darts into a sitting position. The plaster still pins his knee, but his magic is alive inside him again, renewed, and all it takes is a flick of the wrist and it goes flying across the room. A little bit more magic and his knee is slowly healing.

It’s enough, and he rises, gaze immediately flying to the bed. Alec isn’t there.

“Alexander…” Magnus’s voice sounds raw to his own ears and sadness strikes him like he’s never felt before. His Alexander is gone and he couldn’t protect him. He’d failed.

“Magnus?” A familiar groan echoes through the room.

Magnus stumbles around the bed, to the other side, where Alec is lying on the ground. Except, the sight of his husband isn’t what he expects. Lying on that floor isn’t his sixty-five-year-old husband, but a man that looks no older than thirty.

“Magnus?” Alec blinks up at him and grunts as he sits up, his arm wrapped around his stomach.

“Alexander…” Magnus whimpers, stumbling forward and dragging his husband against his chest. “You’re alive.”

Alec’s arms wrap around his back and his fingernails dig into the thin cloth of his shirt. “Magnus. It’s Asmodeus. Asmodeus is—”

“I know, darling. I know. He’s gone.” Magnus clings to his husband tighter and then pulls back. He presses light kisses over Alec’s cheeks, forehead, and jaw and takes a few minutes to get reacquainted with Alec’s lips. It’s been too long, and he needs this as much as Alec does.

Alec whimpers against his lips and holds him closer. “I love you,” he says when they break apart.

As much as Magnus is happy to have his Alec back, as much as he is relieved to have Alec in his arms, he’s also angry. Furious. “How could you, Alexander?”

Alec’s eyes widen. “Magnus—”

“You _left_ me. You packed your belongings and you gave up on us.” The months of anger and agony flood him. There are no words for what he’s feeling, but no matter how much betrayal there is, he can’t bring himself to let Alec go. Not again.

“No!” Alec shakes his head, eyes wide in desperation. “I love you.”

“Then, how could you?” Magnus bares his teeth, cat eyes still vibrant, but this time with unshed tears. “You contacted everyone but me. Did I mean so little to you?”

“No. No, Magnus, _please_. I couldn’t do it anymore. I couldn’t hurt you.”

“Hurt me?” Magnus laughs sadly. “You killed me. The only reason I didn’t give up was because you were still out there. I could still find you and bring you home.”

“Magnus, I…” Alec presses his face in Magnus’s neck. His breath is hot against his skin. “I couldn’t do it anymore.”

“Do you really care what other people think?”

“It’s more than that,” Alec argues softly. “Their looks…reminded me that you deserve more than an old man at your side.”

Magnus shoves Alec’s chest, just so he could stare into the face of the man saying these stupid words. “You’re not an old man, Alexander. You’re _my husband_.”

“Magnus, I’m old.” Alec chest stutters, his gaze not meeting Magnus’s. “You deserve a man or woman who can stay as young as you. You don’t deserve to watch your husband die.”

He thumps his chest. “I get to decide who I want by my side. Not you, Alexander, and certainly not strangers. How dare you?” Rage like he’s never felt before consumes him. He’s not angry at Alec, but rather these stupid thoughts. “I married you, Alec. _You_. I married you for who you are, mortality and even your stupid stubbornness. I married you knowing you were going to grow old. I chose that. You don’t get to decide who I have at my side. You don’t get to decide that there’s someone better out there for me.” By the end of his rant, his chest is heaving, and his anger has calmed. He’s said the things he needed to say and it feels better because Alec has finally heard them.

Alec stares at him, eyes soft and sad. “I’m sorry.”

“You should be,” he snaps. His hands curl around Alec’s upper arms and he squeezes. “If you ever do that to me again, I’ll find you and kill you myself. Am I clear?”

Alec smiles and suddenly he laughs. It’s melodic to Magnus’s ears and he can’t help but smile in return.

“You didn’t answer me, Alexander.”

“I understand,” Alec says between chuckles. “But by the angel, you’re so beautiful when you’re angry.”

Magnus pokes him in the chest. “If you think that means you should get me angry more often, then you’ll sorely regret that.”

His husband’s face softens, and he nods. “I’m sorry, Magnus. I’m so sorry. But can you really deal with this man as your husband?” He gestures to himself.

Magnus inhales and waves his hand. A hand mirror appears, magicked from his own possessions. “I think you need to see something.”

Alec frowns at him, but takes the mirror. He stares into it, eyes wide and his mouth parted in shock. “What? How?”

“Asmodeus. I think…” Magnus licks his lips. “I think he made you immortal, darling. We’d need to do some tests to confirm.”

He frowns at Magnus. “Why would he do that? He’d never—”

Magnus holds up his hand and sighs. He tells Alec about Asmodeus’s words.

Alec groans and presses his fingers into his temple, rubbing it. “What army? What’s he planning on doing, Magnus?”

“I don’t know.” Magnus closes his eyes briefly and takes a deep breath. “We’ll figure it out though, Alexander. Together.” He cups his husband’s cheek. “This never needed to happen. I love you for who you are.”

“I know.” Alec blinks at him with those big, beautiful, hazel eyes and smiles. “But I almost want to send him a thank you note because now we get to spend the rest of our lives together.”

Magnus smirks. “Please don’t. Next, he’ll expect us to invite him to dinner.” It’s a joke in a dark moment and it makes them both chuckle.

“I’d rather not have my father-in-law over for dinner if it’s all the same to you.”

Magnus shakes his head. “Darling, whatever he’s planning—”

“We’ll deal with it.” Alec cups his jaw and kisses him gently. “Whatever he does, we’ll handle it. You said it yourself. Together.”

“Exactly. Together.” Magnus glares. “Don’t you dare think about leaving me again. I _will_ chain you to our bed if I have to.”

Alec’s cheeks flush a beautiful pink and he grins. “I might enjoy that.”

“Don’t tempt me.” Magnus grins, because no matter what his father has planned, they can handle it. He has his Alexander back and that’s all that matters. 

However, what Alec doesn’t know was that his punishment for leaving Magnus was just beginning…

**Notes for the Chapter:**

> I do love comments and kudos! :D


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